Alexander wilson



UNrren STATES ATENT QFFICEQ ALEXANDER \VILSON, OF SHEFFIELD, COUN"Y OF YORK, ENGLAND.

MANUFACTURE OF COMPOUND ARMQR-PLATES.

SPECIFICATION forming part; of Letters Patent No. 362,806, dated May 10, 1887.

Application filed April 0, 1887.

To all whom it may concern.-

Be it known that I, ALEXANDER WrLsoN, a subject of the Queen of Great Britain, residing at the Cyclops .Vorks, Sheffield, in the county of York, England, steel-maimfacturer, have invented certain new and useful Improvements in the Manufacture of Compound Armor-Plates, of which the following is a specification.

The object of this invention is to produce compound armor-plates with a very hard face and an extremely soft and tough back. To effect this I proceed as follows: I take a wrought-iron fibrous plate-say about fifteen inches thick-which has been previously built up from a number of thinner ones in the usual manner, and while hot from the rolls hammer or pressand put it into a cast-iron or wrought-iron box or mold. The mold is made internally of the proper length, breadth, and depth. The depth for the plate in question would be about twenty-eight inches. This would enable me to fuse onto the exposed surface of the fibrous iron plate a layer of ingot-iron about thirteen inches in thickness, thus forming a plate twenty eight inches thick. I then take the plate out of the mold as soon as desirable and put it into a reheating-furnace, and after reheating it to the proper temperature I subject it to the action of a rolling-mill hammer or press until it becomes reduced to about eighteen inches in thickness. This is now what I term the iron backing of the compound plate. I then put it into the mold again, the depth of which can be easily altered, and then run or fuse onto the other side of the fibrous iron plate a layer of hard steel-say about eight inches in thickness. The plate is now in its rough state about twenty-six inches thick. I then take the plate out of the mold, and put it into the same or other reheating-furnace and expose it to the action thereof for a comparatively short time, after which I roll, hammer, or press the plate to the desired or finished thicknessviz., twenty inches. The plate is then allowed to cool. Afterward it is planed and otherwise machined to the proper form and dimensions.

It will be observed that I subject the backing portion of the plate to a great amount of Serial No. 234,259. (No model.)

mechanical manipulation and pressure to increase its strength and toughness before I fuse on the liard-steel face. This I consider most important, as the latter portion of the plate can be made sufficiently hard to prevent penetration without its having to undergo any mechanical pressure or manipulation whatever, although in some cases I may prefer to do so, as in my former methods; and in order that my improvements shall be further understood, I may say that I make the ingot-iron, which I fuse onto the fibrous iron plate to form the backing, as soft and as low in carbon, or nearly so, as the best brands of Yorkshire irons, which, when rolled or hammered, will give a tensile strain of twenty-six to thirty tons per square inch, and the steel which I propose to fuse onto the fibrous iron plate to form the face I make of a very high temper-say containing from 1.25 to 1.5 per cent. of carbon, or thereabout, which will be very hard and will offer great resistance to penetration of projectiles. The ingot iron and steel can be pro dueed by either of the processes commonly known as Bessemer and "Siemens-llIartin. The center portion of the plate I make of the best puddled fibrous iron.

It will now be easily seen that I can produce a plate which will have a face as hard as can be planed or otherwise machined, which will enable it to break up any projectiles that may be fired against it and will resist the penetration thereof, while the back of the plate will be made tough and ductile, having also great tensile strength to enable it to better support the front layers of the plate, and by retaining the fibrous iron core or center portion I produce a plate which is not homogeneous, butstratified. Therefore any fractures or cracks which may be produced on the hard face of the plate by the impact of projectiles will not extend through the full thickness of the plate. This I also consider most important, as it is a well-known fact that homogeneous plates made wholly of steel or other hard metals, either in layers or otherwise, have this failing, and that all cracks produced on the surface by impact or otherwise do extend right through the full thickness of the plates, there being no fibrous strata to prevent it.

Although I have specified the various thicknesses and tempers .of steel and iron layers of a twenty-inch compound plate made by this improved method, it must be understood that I do not bind myself thereto, as these may be 5 varied without departing from my invention;

but

What I claim as my improvements in the making of compound armor-plates is The process hereinbefore described of manu- [O facturing armor-plates, consisting in taking a' wrought-iron fibrous plate hot as it comes from the rolls or other forging apparatus and puttingit into a mold and casting onto one of its 

